Test Effort Estimation

Why Test Effort Estimation

Effort

Expected Testing outcome

Estimate of what ??

ResourcesTime

Skill

Who does the Test Estimation?

“Test Manager”

Identifying the

compo

nents

Developing Test Plan

Identifying Task

Computing size

Esti

mating test Effort

Preparing Test Plan

Validating Estimation

Steps in Test Effort Estimation1

2

3

4

5

6

7

Identifying the Components to be Tested

1

Common Components

• GUI Controls• Screens• Functions• Reports

Identifying a Test Strategy

2

On what basis test strategies are formed?

Based on the components indentified

Functionality1

Functionality12

TestStrategy1

TestStrategy2

TestStrategy3

TestStrategy4

Identifying the tasks to be performed

One time task

Repetitive activities

3

One time tasks

– Preparing test strategy– Understanding

customer requirements

– Establishing communication plan

Repetitive tasks

– Identifying test condition

– Developing Test cases

– Generating Test Data

– Reviewing test condition, test case, test data

– Executing test cases

– Reporting test results

Computing software sizeBased on complexity

4

Levels of complexity Low complexity

Web applications Desktop applications

Medium complexity Two tier/three tier application

High complexity Multitier applications

Estimating Test Effort

4

1

2

3

5

INPUTS

Test Effort

Durations Infrastructure Resources Expertise

requires

The estimate of test effort Forwarded To

Management TeamAccept Reject

Preparing test plan based on inputs

6

Test plan is prepared based on:• Scope of testing• Risk involved• Test completion criteria• Deliverables at different stages• Scope of defect management• Requirements for the test environment

Validating the estimate at the end of project• All assumptions are re-validated• Done after the project • Determines if the estimate is correct

Challenges Lack of clarity Inaccurate estimation Delay in project delivery Lack of proper test

planning Lack of testing expertise Selection of wrong test

data Lack of proper planning

for the test environment

Test effort estimation techniques Function Point (FP) Constructive Cost Model (COCOMO) Test Point Analysis(TPA)

Function Point Analysis• Function points are a unit measure for

software• It involves breaking the system into small components which in turn identifies the function points

The size of application is calculated using 5 major components External Inputs External Outputs External Inquires Internal Logical Files External Interface Files

Benefits of FPA• Language and technology independent• Estimate cost, effort, schedules of projects

that use prototype and spiral models• Helps in project estimation

COCOMO Model

• It categorized software products into three classes– Organic systems“refers to simple projects developed by a few experienced

team”

– Semidetached systems“refers to intermediate projects between organic and

embedded”

– Embedded systems– “refers to complex projects”

COCOMO model equation

• Effort =a1 * (KLOC)• Tdev=b1*(Effort)

KLOC – the estimated kilo lines of code a1, a2, b1, b2 are constants for different categories of

software products Tdev is the estimated time to develop the software in

‘months’ Effort is the total development effort required to

produce the software in ‘programmer months’.

a2

b2

Benefits of TPA

• Analyst independent• Tests quality characteristics

Thank you